Two types of work are proposed: (1) Nuclear magnetic resonance (NMR) study of muscle and collagen in the growth and aging processes. The state of water, its interaction with ions and contractile proteins in muscle and collagen, and the corresponding changes in the course of aging will be studied. The spin-lattice relaxation time (T1) of water protons in skeletal muscle and tail tendon from mice and rats of different ages will be studied as a function of temperature and resonance frequency. The dipolar splitting of H2O and quadrupolar splitting of D2O adsorbed on oriented myosin and collagen fibers will be studied at different temperatures and humidities. T1 and 23Na in muscle from new-born to senile mice and rats will be measured to determine the change of the interaction between sodium ions and cell components. (2) The mechanism of collagen contraction will be studied by other physical methods, such as measurements using cathetometer, spectrophotometer and polarimeter. The interaction of calcium ions, ATP and water with native, intact and soluble collagen will be studied at different concentrations, pH's, temperatures and environments in order to understand the mechanism of collagen contraction under physiological conditions.